<select name="men_id" <?=$estilo;?>>
    
    <?php if (!isset($_SESSION['men_id'])) { ?><option value="">Selecione um menu</option><?php } ?>
    <?php
    if (isset($_SESSION['men_id'])) { $onde_menu = "WHERE men_id='{$_SESSION['men_id']}'"; } else { $onde_menu = ""; }
    $sql_menu = "SELECT * FROM menu $onde_menu ORDER BY men_nome";
    $res_menu = sql($sql_menu);
    while($linha_menu = mysql_fetch_array($res_menu)){
    ?>
    <option value="<?=$linha_menu['men_id'];?>" <?php if($linha_menu['men_id'] == $men_id) { echo "selected"; } ?>><?=$linha_menu['men_nome'];?></option>
    <?php } ?>

</select>